If you have spray paint lying around in your home or your office, then you may be wondering how flammable or combustible it is and whether you should take steps to store the paint safely? This is a good question and the answer isn’t as straightforward as it might seem, because there are many different types of paint. So, I’ve tried to examine the major categories of paint to get the answers you need.
Some forms of paint are highly flammable or combustible, such as spray paints, which are particularly flammable when in aerosol form. Whereas a water-based paint, such as acrylic paint, can even be flame-retardant, thanks to the water content of the paint.
Lets take a look at the difference between flammable and combustible. We will also talk about the specific hazards associated with the different types of paint. So, here’s what you need to know about paint and fire.
Also read: What Makes Something Flammable?
Table of Contents
Flammable vs Combustible
The terms flammable and combustible in general English are almost interchangeable, right? If you looked at say lighter fluid, you would be comfortable using either word to describe the fact that it easily catches fire when exposed to a flame.
However, from a technical perspective, there is a subtle difference between the two. The US Department of Labor, OSHA standards, which follow internationally agreed standards, define combustible liquids and flammable liquids based on their flash point temperatures.
What is a flashpoint? It is the temperature at which a substance will burn.
Here are the old standards:
They also have two separate definitions for these terms – one for the construction industry and one for the general industry.
So, combustible liquids in construction must have a flashpoint at or above 140 degrees Fahrenheit but it cannot exceed 200 degrees Fahrenheit.
This is very different from the general industry standard which says that a combustible liquid must have a flashpoint of 100 degrees Fahrenheit and above.
Whereas flammable liquids in construction must have a flashpoint below 140 degrees Fahrenheit but also must not have a vapor pressure that exceeds 40 lbs. per square inch when the substance is at 100 degrees Fahrenheit.
In general industry, on the other hand, the definition is that a liquid that has a flashpoint below 100 degrees Fahrenheit is categorized as a flammable liquid.
These two different standards aren’t because the government is trying to be difficult. The construction industry standards were established in the Construction Safety Act, whereas the more general industry standards were simply agreed by consensus in industry.
Though there is a slight exception when that liquid is mixed with another that has a higher flashpoint and when the other liquid takes up at least 99% of the total volume of the liquid.
They did change the flammability classifications though.
OSHA now says, a flammable liquid is any that has a flashpoint below 199.4 degrees Fahrenheit (93 Celsius).
This table should make it more clear:
|Flammable Liquid||Flashpoint < 199.4 degrees F (93 C)|
|Non-Flammable Liquid||Flashpoint > 199.4 degrees F (93 C)|
When we look at the issues of combustible and flammable in the rest of this article, we will be assuming that we’re using the general industry standards and not the definitions specific to the construction industry.
Also read: Is Paint Thinner Flammable? Technically No…
There is no set definition of the word “paint”. Many products can be used to coat other substances and they are all referred to, generically, as “paint”.
Thus, some paints are, indeed, combustible, while others are flammable, and others are completely flame-retardant.
Much depends on what the base of the paint is and, as you’d expect, paints with flammable bases, such as alcohols, are nearly always capable of catching fire easily.
However, you should also be careful of water-based paints. While the majority of these paints are flame-retardant, there are some exceptions to this rule and those products are also flammable.
Now, let’s take a look at some common paints and their flammability vs combustibility (or lack thereof).
Also read: Is Transmission Fluid Flammable? Yes and No…
What About Spray Paint?
These gasses are highly flammable.
This means that, in practice, a damaged spray paint can is very dangerous.
Not only can the fumes from the can ignite but there is a strong possibility of flashback which will then cause the can to explode – think of it as a sort of paint grenade but one which throws actual shrapnel.
Take a look at what happens when butane (used in spray paint) is exposed to fire:
Thus, all spray paints should be stored carefully and kept away from children, etc. as they might accidentally damage the can.
Also read: Is Ink Flammable? (Pen/Printer)
Latex paint dries to give a sort of rubbery feel to the finished paint and it is usually not at all flammable.
This is because most forms of latex paint do not use any flammable solvents and thus there is no vapor to become combustible.
Here is a special fire-retardant latex paint in action:
You still don’t want to allow young children access to these paints unsupervised, but there is usually no danger in storing them in any safe place in your home – you can be confident that your latex paints won’t burn or explode.
Also read: Is Soap Flammable? Will it Burn? It Depends…
Acrylic paints are also, usually, water based and thus aren’t likely to catch fire.
Make sure to read the packaging carefully though as some water-based paints also include other solvents. If you see words like “oil”, “epoxy”, “varnish”, “petroleum distillates” or a combustion warning on the box – you should treat the paint as flammable.
Otherwise, you can safely store acrylic paints anywhere in your home as long as they are out of reach of small children.
Also read: Is Glitter Flammable?
Does Paint Burn?
Technically speaking, no, the liquid in the paint cannot burn – it’s the mixture of paint fumes and the air that burns.
The heat from the fire raises the temperature of the liquid, which causes evaporation which releases more vapor that continues to fuel the fire.
The most flammable liquids, such as gasoline, can give off enough vapor at minus 40 degrees Fahrenheit, meaning that they catch fire very easily.
Both flammable and combustible liquids are capable of giving off enough vapor at room temperature that they will easily ignite, in the presence of the right heat source, and create a serious fire hazard.
One thing to note is that liquids present a more serious danger than flammable solids because they can easily flow in many directions – thus small amounts of flammable liquids can easily coat a large area of space, something that a solid cannot do.
They also may be subject to “flashback” which is when the liquid is stored in an area with a poor level of ventilation.
The vapor escapes from the container in which the liquid is stored and settles in the space and eventually, if it reaches high enough concentrations and a heat source is found, it can ignite and then travel all the way back to the container with the liquid in it.
Thus, it is vital to store flammable or combustible paint in way that minimizes this risk and ensures the safety of both you and those around you.
What About Paint Fumes?
Assuming that the base of the paint is flammable or combustible, then the paint fumes are all that is flammable as we said at the beginning – the liquid paint cannot burn, it is the vapor that burns and the words “vapor” and “fumes” are entirely interchangeable.
This means that flammable paint must be stored properly, and this includes making certain that the containers that it is kept in are properly sealed.
When breaks or leaks occur in these containers then you are significantly increasing the level of fire risk that the paints present.
Also read: Is Glue Flammable? Sometimes…
Hazards Of Flammable/Combustible Products
Other than fire or explosions – many flammable and combustible chemicals can cause injury to your health by direct exposure or ingestion.
You should read any directions on the packaging of your paints for use, carefully, to prevent chemical burns or poisoning. Also, make sure to dispose of all paints properly after use.
Is paint flammable/combustible? Well, it depends. As you can see there’s no single substance of “paint” and while some paints are, indeed, highly flammable and present a genuine fire hazard, others aren’t such a risk, thanks to being made from materials which resist flames.
The best rule of thumb is that if you are uncertain whether the paint is flammable or not, is to treat as though it is and store it safely in a place where it is unlikely to come into contact with a spark, flames, or any other source of fire. Flammable liquids can create severe fire hazards and wherever possible, you want to minimize the risks of using and storing them.